The following relates generally to wireless communications, and more specifically to adaptive feed-forward power amplifier linearization methods using adaptive filters.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems, (e.g., a Long Term Evolution (LTE) system). A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE).
A wireless device may utilize a power amplifier (PA) to amplify a signal to be wirelessly transmitted. In some cases, PAs may exhibit non-linear behavior, for example during high power transmissions, that produce emissions outside of the desired frequency band, thereby introducing interference in neighboring frequency bands. A device may use PA linearization techniques to reduce the magnitude of out of band emissions. However, conventional methods used to linearize the PA may decrease efficiency of the transmit circuit or fail to accurately remove non-linearity from the transmit signal.